---
title: "JavaScript → Kotlin"
description: "Master Kotlin programming language from JavaScript background. Learn coroutines, Android development, functional programming, and JVM ecosystem."
---
## Why Learn Kotlin?

Kotlin is a modern, concise, and safe programming language that runs on the JVM. It's the preferred language for Android development and offers excellent support for server-side development, web development, and cross-platform applications.

### Key Benefits

- **Android Development**: Official language for Android development
- **Coroutines**: Powerful asynchronous programming with coroutines
- **Functional Programming**: Rich functional programming features
- **JVM Ecosystem**: Full access to Java libraries and frameworks
- **Cross-Platform**: Kotlin Multiplatform for shared code
- **Type Safety**: Null safety and strong type system
- **Interoperability**: Seamless Java interop

## Learning Path

This course is designed for JavaScript developers who want to master Kotlin. We'll start with syntax comparison and gradually move to advanced topics like coroutines, Android development, and modern Kotlin features.

### Module Overview

1. **Kotlin Introduction** - Language philosophy and setup
2. **Syntax Comparison** - Mapping JavaScript concepts to Kotlin
3. **JVM Ecosystem** - Understanding the Java Virtual Machine
4. **Functional Programming** - Higher-order functions and lambdas
5. **Coroutines** - Asynchronous programming with coroutines
6. **Object-Oriented Programming** - Classes, interfaces, and data classes
7. **Android Development** - Mobile app development basics
8. **Web Development** - Spring Boot and backend services
9. **Mobile Apps** - Jetpack Compose UI development
10. **Cross-Platform** - Kotlin Multiplatform projects
11. **Testing & Debugging** - Testing frameworks and debugging
12. **Projects** - Real-world applications
13. **Common Pitfalls** - Avoiding common mistakes
14. **Idiomatic Kotlin** - Best practices and optimization

## Prerequisites

- Basic JavaScript knowledge
- Understanding of programming concepts
- Familiarity with object-oriented programming

## What You'll Build

- Android mobile applications
- Web backend services
- Cross-platform applications
- Real-time chat applications
- E-commerce platforms
- Data processing applications

## Modern Kotlin Features

- **Coroutines**: Asynchronous programming made simple
- **Flow**: Reactive streams for data processing
- **Jetpack Compose**: Modern declarative UI
- **Kotlin Multiplatform**: Share code across platforms
- **Smart Casts**: Automatic type casting
- **Extension Functions**: Extend existing classes
- **Data Classes**: Concise data containers

## Start Learning

Begin your Kotlin journey with our comprehensive modules. Each module includes interactive code examples, practical exercises, and real-world projects.

<UniversalEditor title="Hello Kotlin" compare={true}>
```javascript !! js
// JavaScript
let message = "Hello, World!";
console.log(message);

function greet(name) {
    return `Hello, ${name}!`;
}

const result = greet("Kotlin");
console.log(result);
```

```kotlin !! kt
// Kotlin
val message = "Hello, World!"
println(message)

fun greet(name: String): String {
    return "Hello, $name!"
}

val result = greet("Kotlin")
println(result)
```
</UniversalEditor>

Ready to start your Kotlin journey? Let's begin with the [Kotlin Introduction](./js2kotlin/module-00-kotlin-introduction)! 